"Employment of Flak with the Field Army" from Tactical and Technical Trends

The following U.S. military intelligence report on German employment of antiaircraft artillery with the army during WWII
was originally published in Tactical and Technical Trends,
No. 41, December 30, 1943.

[DISCLAIMER: The following text is taken from the U.S. War Department
publication Tactical and Technical Trends. As with all wartime
intelligence information, data may be incomplete or inaccurate. No
attempt has been made to update or correct the text. Any views or
opinions expressed do not necessarily represent those of the website.]

EMPLOYMENT OF FLAK WITH THE FIELD ARMY

American antiaircraft is called "AA", British is called "Ack-Ack" and
German is called "Flak" which is an abbreviation for "Flugzeugabwehrkanone"
(antiaircraft gun). Flak generally means the fire from such guns rather than the
guns themselves. The fundamental methods of control and operation used by the
Germans are almost the same as those used in the United States and British Armies.

A British summarization based on translated German manuals, including
information as of late 1940, contains some principles on the employment of Flak
with the field artillery, and developments in the doctrine of tactical employment
during the war, especially in relation to the increased importance of the ground
role: Additional details concerning the employment of German antiaircraft artillery are found
in Tactical and Technical Trends, No. 35, p. 3
and "German Antiaircraft Artillery," MID Special Series No. 10 (8 Feb 1943).

* * *

a. General

(1) The forces available for the defense of important installations are in
general limited; dispersion over wide areas prevents effective defense of vital
points. They must, as far as possible, be concentrated at the most important
points in accordance with the intentions of the commander.

(2) Flak operations in association with the army should be characterized,
above all, by mobility in deployment. War of movement demands foresight in plans
and preparations together with rapidity in decision and action.

(3) Correct action in all situations demands prompt information on
changes in the ground and air situation and on the intentions of the Higher Command,
together with the allocation of definite tasks. The Flak commanders must work
in close liaison with the army commanders to whom they are attached and keep
subordinates fully informed.

(4) The majority of the Flak must always be ready for action. Frequent
moves of short distances should be avoided; moves of longer distances are less
frequent and cause less interruption. Preparations for a change of position should
not involve units going out of action prematurely or being held in reserve.

(5) Combat of air reconnaissance is an important task of the Flak artillery
in a war of movement. All positions within effective range should therefore engage
reconnaissance aircraft, though exceptions to this may sometimes be required to
avoid giving away one's own dispositions and intentions.

(6) Concealment from ground observation is as important as camouflage
against aircraft, especially when within range of enemy artillery. In such
conditions concealment (especially of the gun flashes) will override other
considerations in the choice of positions. Suitable earthworks will be required
and positions should, if possible, be occupied by night.

(7) Flak artillery on the march and in position must guard against enemy
attacks by mobile forces (i.e., tanks, airborne troops) or by infantry which has
broken through or deployed during an advance. Surprise air attacks must be
guarded against by light Flak during occupation of, and withdrawal from positions,
and when marching through defiles or over bridges.

b. Employment Against Aerial Targets

(1) Protection of the Assembly Area

Protection of assembly areas, approach roads, etc., is effected by a
systematic deployment of the heavy batteries.* As a rule the heavy batteries
should also be able to cover the greater part of the approach route; siting too near
the line of march should be avoided.

As a protection against low-flying and diving attacks the light batteries
are deployed so as to cover the whole assembly area or points especially vulnerable
to such attack.

(2) Protection of the Advance

The object of concentrations of heavy batteries should be to protect the
entire area of advance of the army formations against high-level attacks and
reconnaissance. The light batteries are deployed as required, for the protection
of individual columns or groups against low-flying and diving attacks. The guns
are normally placed near the line of march; as they must be especially close in
for the protection of valley roads. Deployment on hills wastes time and makes
it possible for an aircraft to fly below the fire of guns thus placed; it offers no
advantages and exposes the troops to danger from fire at very low angles of sight.

In night marches, when weather conditions are favorable for air attacks,
Flak defense must be provided, but limited to the protection of defiles, inhabited
localities, river crossings etc.; for this, concentrations of light Flak should be formed.

The forward movement of the Flak during the advance must be carefully
organised, right of way being arranged with the higher authorities. Light troops
will normally use the main advance route, but heavy troops will, as far as possible,
use parallel routes.

(3) Protection of Motorized Troops on the March

Protection against high-level attack by heavy Flak is required only at
assembly, entrucking and detrucking areas, halts and especially dangerous points
the route such as bridges, defiles or intersections.

Protection against low-flying and diving attacks must be assured by the
light Flak units allotted to the motorized formations. These should be allotted to
columns by platoons or even by individual guns.

(4) Protection of Troops on the Battlefield

Both in attack and defense, the tasks of the Flak artillery are the same.
They include the engagement of enemy reconnaissance, artillery positions,
observation aircraft, and the AA defense of infantry positions, artillery reserves
and armored cars, whether at halt or attacking.

Heavy batteries are mostly deployed in the artillery zone. Engagement
of enemy observation aircraft is only possible when the effective range of heavy
batteries extends far behind the enemy positions.

The placing of the Flak must be co-ordinated with that of the artillery and
infantry; in general the Army requirements have precedence.

In defense, individual batteries may be moved forward to prevent enemy
reconnaissance. Arrangements must be made beforehand for their rapid
withdrawal behind the main front line to prepared positions. Close liaison with units
on the flanks is necessary to guard against surprise by enemy ground forces.

During prolonged fighting, well-timed changes of position of individual units
make it more difficult for the enemy to locate and range on Flak positions.

(5) Protection in Delaying Action or Withdrawal

In the delaying action the main effort should be directed to the engagement
of reconnaissance aircraft, with a view to concealing the intention to withdraw. In
withdrawal the principal object is AA protection through defiles, and the like.
Light batteries are allotted as required to main lines of resistance.

(6) Protection of River Crossings

A distinction must be drawn between the protection of bridges or pontons
as distinct from crossings by troops; in the first case the primary object is defense
against low-flying or dive-bombing attacks, while in the second complete protection
is required and, in addition, protection of assembly areas and arrival and departure
routes. In the advance, heavy and light batteries, as well as searchlights and
advanced aircraft observation posts, must be transferred to the far side of the
river as quickly as possible.

c. Employment Against Ground Targets

(1) Heavy Flak

As a general rule heavy Flak only engages ground targets in an emergency
though in special cases it may be deployed specifically with a view to its use in
a ground role. Preparations should always be made for a rapid return to the AA role.

Batteries deployed in a quadrilateral formation in the AA role must
generally reckon with having to leave out one or two of the guns when engaging
ground targets.

When heavy Flak is deployed specifically for the engagement of ground
targets, the guns should be placed in line at intervals of 30 to 50 yards, with the
instruments behind the center of the battery or offset to one side. When the heavy
batteries of a battalion (Abteilung) are deployed in the ground role as a whole, the
battalion commander prescribes the duties of the batteries and the zone of
fire and sometimes individual targets.

(2) Light Flak

As a general rule, light Flak only engages ground targets in an emergency,
but sometimes it is used to reinforce the fire of the heavy infantry weapons. The
engagement of ground targets is carried out from open positions by direct fire.
Every position must, by natural or artificial concealment, blend into the landscape
and not be immediately recognizable. Dug-in emplacements may be made if time
permits. Positions which allow rapid occupation unobserved by the enemy are
particularly suitable. Alternative positions should always be reconnoitered.

Tactical considerations and the terrain will decide whether the gun is
fired from its trailer or dismounted. Firing from the trailer severely limits
the field of fire but greatly increases mobility. Firing with wheels removed affords
better concealment, field of fire and accuracy.

In principle, light Flak temporarily engaged in a ground role must always
be able to resume the AA role.

d. Developments in Tactical Employment

Translated German documents and experiences in the field have contributed
much information concerning the principles governing the employment of Flak
operating with the army. Some of the developments in the enemy's tactics since
the beginning of the war indicate that in some respects (especially in regard to
heavy Flak) his doctrine has undergone important modifications.

The duties of Flak artillery in the field as described in the manuals are
primarily (and almost exclusively) AA defense, with the engagement of ground
targets as a secondary and relatively unimportant role, only to be assumed in
emergency. Although the possibility is admitted of using light Flak to reinforce
the fire of the heavy infantry weapons and heavy Flak to complement AT and field
artillery, such employment is regarded as exceptional. There is nothing to suggest,
for example, the present importance of the 88-mm (3.46 in) Flak gun in German
AT gunnery; this gun was tried out in a ground role in the Spanish Civil war, won
its spurs against French tanks in the Battle of France and has virtually held pride
of place amongst AT weapons in all subsequent campaigns.

The transition from the defensive doctrines of the manuals to the more
active modern conception seems to date from the introduction of the
Flak Corps. These formations first made their appearance in the Battle of France.

e. Heavy Flak

(1) General

In operations with the field army the 88-mm gun, as a result of its high
mobility, has become almost the universal weapon of heavy Flak; larger calibers
are usually found only in areas of static defense. For the organization of German AA defense
see Tactical and Technical Trends, No. 28 p. 4.

Guns are commonly fitted with shields to protect the detachments against
small arms fire, with a telescopic sight for the engagement of ground targets, and
with a dial sight for field artillery tasks. In the interests of mobility fire-control
equipment is frequently left behind. In addition to time fuze HE ammunition, AP
and percussion-fuze HE ammunition is normally carried. Engagement at night
presents special problems, since muzzle flashes readily give away the gun positions;
fiashless propellant, however, which is now believed to be in general use in the
field, provides a corrective.

The 88-mm gun can be brought into action very rapidly, possibly in about
two minutes; it can, if necessary, fire from its trailer, though only against ground
targets. Experiments were made with a self-propelled model, but it is not believed
to have been a success and nothing has been heard of it in action. The normal
mounting is conspicuous owing to its height and is consequently extremely vulnerable
to artillery fire. Whenever possible, therefore, it is dug in so that only the barrel
appears over the top of the emplacement, though in practice the time factor and
the frequent moves rarely permit concealment to be effected. The destruction of
hostile OPs constitutes an indirect method of protecting heavy Flak guns and no
opportunity to accomplish this is missed.

Eighty-eight millimeter guns may open fire on tanks at 2,500 yards with
fair prospects of success, but they are most effective up to ranges of about 1,000
to 1,500 yards. In default of other targets they may engage up to 4,000 yards,
while with the aid of an advanced OP, targets such as troop concentrations have
sometimes been engaged up to 6,000 yards range.** Examples of penetration
performance with the 88-mm Flak 36 (see
Tactical and Technical Trends, No. 29, p. 5) the
most common model of this gun, are given below; they are based on trials
carried out against homogeneous armor:

In rear areas heavy Flak fulfils its normal task of AA protection of ports,
airfields, dumps, headquarters and communications zones. Predictors and/or
auxiliary predictors are employed and radiolocation equipment may also be
allotted. Although the AA role is the primary consideration, Flak batteries even
in rear areas are normally provided with AP and percussion-fuze HE ammunition
and can therefore operate against hostile troops or armor which may have broken
through; their degree of preparedness to meet such attack naturally depends on
the distance behind the front.

(3) Employment in Forward Areas

It is in the employment of heavy batteries attached to the army for operations
in forward areas that the present-day methods of the Germans show the greatest
disparity from the principles of their pre-war manuals; these contemplated a
primary AA role, a secondary AT role, and sometimes employment in a field
artillery role. It may be said that the former secondary role has now assumed
virtual priority, for experience has shown that the 88-mm gun has become an
indispensable complement to the AT artillery of the army. A proportion of the
heavy batteries in forward areas is still employed in an AA role, primarily for
the protection of advanced airfields, and in periods of inactivity or preparation
the AA role predominates; for example an assembly prior to an attack will
usually be protected by heavy guns and under these conditions the ground role will
only arise the event of surprise attack. However, once action has begun whether
in attack or defense (and particularly when armored forces are involved), the AA
role becomes the exception for the heavy Flak guns, all of which are usually
employed against ground targets; in case of necessity even guns originally deployed
for the AA protection of advanced airfields are sometimes pressed into service
as AT weapons. The extent to which heavy Flak guns are now employed in a ground
role is well illustrated by German press claims of successes by Flak units operating
with the army; such successes commonly show the greater number of targets to
have been armor and other ground targets rather than aircraft.

Light Flak guns are of particular value against surprise attack owing to
the rapidity with which they can be brought into action. The 20-mm Flak 30, for
example, can be brought into action in about half a minute and all light guns can,
in extreme emergency, be fired (though with limited traverse), from their trailers;
in addition self-propelled models of the 20-mm and 37-mm calibers are known to
exist and can engage both aerial and ground targets. As in the case of heavy guns,
light guns in the field are usually fitted with shields for protection against small
arms fire. They are also fitted with Flak sights and/or telescopic or linear sights,
and carry AP in addition to percussion-fuze HE ammunition. Against ground targets,
particularly "soft-skinned" motor transport, they may engage up to about 800
yards, but are most effective at ranges up to about 300 yards. Examples of
penetration performance of the 20-mm Flak 30 firing AP shell against homogeneous
armor, are:

Range

Thickness of armor

(yards)

30°

Normal

100

31 mm (1.22 in)

48 mm (1.89 in)

200

29 mm (1.14 in)

44 mm (1.73 in)

300

27 mm (1.06 in)

41 mm (1.61 in)

400

25 mm (0.98 in)

38 mm (1.50 in)

(2) Employment in Rear Areas

In rear areas light Flak troops fulfill their normal function of AA protection
of airfields, bridges, railway stations and the like. Batteries in this role are
generally deployed as a whole, the guns being sited in sections. While the AA role
predominates, these batteries constitute an important element in the ground defeat
scheme of the vital points they are protecting and are prepared to engage armored
or other forces which may succeed in penetrating so far.

(3) Employment in Forward Areas

Light batteries attached to army units in forward areas may also operate
as a whole, but platoons are commonly detached for particular tasks. These are
usually spaced at intervals along the column or placed at particularly vulnerable
points along the route, such as bridges, defiles or crossroads, and subsequently
"leapfrogged". Their primary task is to protect the column against attack by
low-flying aircraft, but they may also engage ground forces.

In battle, light Flak units provide protection for headquarters, field
artillery concentrations and engineer units, troop concentrations, motor parks,
etc. It is also sometimes found necessary to allocate a light platoon (3 guns) to
a heavy Flak battery engaged in AT work, the two light guns belonging to the
heavy battery presumably providing in certain circumstances insufficient protection.
In all these tasks the AA role predominates, but engagement of troops and armor
is also highly important and of frequent occurrence. During tank attacks, light
guns, as well as the heavies have been known to engage armor to the exclusion of
aerial targets, leaving the army troops to protect themselves against air attack by
rifle and light machine-gun fire; German documents show that the principle of
self-protection against low-flying attack by means of small arms fire is inculcated
in army training pamphlets (see
Tactical and Technical Trends, No. 30, p. 6).

It will be seen that, unlike heavy Flak, in which the suitability of the
equipment for the ground role and its high penetration performance have brought
about such a profound modification in the conception of tactical employment, the
methods of employing light Flak with the army adhere fairly closely to the principles
of the pre-war manuals; although the ground role has increased in importance for
light guns, it still remains very much the exception, rather than the rule.

g. Searchlights

A light (600-mm) searchlight is allotted to each light Flak platoon and is
usually deployed with it in the defense of advanced landing fields and other
vulnerable points. Light Flak platoons operating with the army in forward
areas, however, are not normally accompanied by their light searchlights.

Heavy (150-mm) searchlights are organized in separate units. They are
rarely deployed in areas where contact with enemy ground forces is likely; the
more advanced heavy Flak batteries operating in an AA role generally rely for
engagements at night on mobile radio location equipment, and/or the 600-mm searchlights
of the light Flak platoons.

*A heavy battery normally consists of four or six heavy guns, usually 88-mm
caliber, with two or three (20-mm) guns for close protection. A light battery
normally consists of twelve 20-mm guns frequently subdivided into sections of
three guns each. There is a medium battery of nine 37-mm guns. Two light
batteries and one medium, or 3 light batteries, together with a searchlight battery
of 16 600-mm searchlights, and a headquarters form a battalion. A regiment may
contain from three to five battalions, and a division, two to five regiments.
**The telescopic sight is in fact graduated up to 10,340 yards and it would be
theoretically possible to engage targets up to this range. For indirect fire (using
the dial sight) the maximum range of the 88-mm AA 36 is 11,445 yards with
time-fuze HE and 16,132 yards with percussion-fuze HE. Corresponding maximum
ranges with the recently introduced 88-mm AA 41 equipment are: